Qatar is following the example of its neighbor Saudi Arabia and buying 62 German Leopard 2A7+ tanks. Saudi Arabia is buying at least 244 Leopard 2A7+ tanks from Germany. Qatar is also buying 24 PZH-2000 155mm howitzers. The deal for the tanks and artillery is worth $2.48 billion and includes spare parts, training, and tech support.
The PzH (Panzerhaubitze, or armored howitzer) 2000 was built to replace the 1950s era American M-109s in German service. The PzH 2000 is larger (at 56 tons, compared to 28) than the M-109, has a longer range gun, a smaller crew (three compared to four men), and more capabilities and features as well. This enables the PZH 2000 to deliver more accurate fire over longer distance and do it quicker than other artillery.
The Leopard 2A7+ is an upgrade of the 2A6 model. That upgrade included more armor on the sides and rear (especially to protect against RPGs), more external cameras (so the crew inside could see anything in any direction, day or night), a remote control machine-gun station on top of the turret, better fire control and combat control computers and displays, more powerful auxiliary power unit and better air conditioning, and numerous other minor improvements. This increased the weight of the tank to nearly 70 tons.
The Leopard 2A7+ has added improvements to mobility (engine, track laying system, wheels, and related gear), better soundproofing for the crew, more, and better, thermal sights, and more effective ammunition for the 120mm gun (fragmentation shells that detonate above or behind a target).
Until three years ago the 55 ton Leopard 2A6 was the current version and is a contemporary of the American M-1. The 2A6 model has a stabilizer (for firing on the move) and a thermal imager (for seeing through night, mist, and sand storms). Germany has been selling less capable refurbed 2A4s since the 1990s (after the Cold War ended and the German army was much reduced in size). This enabled many nations to inexpensively upgrade their aging armored forces. In the last decade, many nations have upgraded their Leopards to the A6 standard. Many nations prefer to continue upgrading their Leopards, mainly because there are no new tanks to buy, thus the appeal of an upgrade to the 2A7+ standard.
Saudi Arabia is concerned about Iran, which has a force of 1,500 much older tanks (most of them Russian T-72s and T-54/55s). Saudi Arabia has 1,300 tanks, most of them older American M-60s and French AMX-30s. But the Saudis also have 370 U.S. M-1s and more on the way. The 244 Leopards will increase the Saudi edge. The Saudis also have the money to buy spare parts for their modern tanks and Western instructors to provide the best training. But the Iranians are better soldiers, so they might have an edge there.
Qatar and Saudi Arabia have a mutual support treaty with each other and other members of the GCC (Gulf Cooperation Council). For more than a decade the GCC has made plans to deal with the Iranian threat. The key here is coordinating the air and naval forces of the GCC members and close cooperation with foreign (especially American) allies. The GCC weapons are more modern and numerous than what the Iranians have. Add in American, and other foreign forces stationed in the Gulf, and the Iranians are up against a formidable force. While the Iranians have always been better fighters than the Arabs, the GCC states have sought to give their troops more training, using Western trainers and techniques. This may not have eliminated the Iranian advantage but it closed the gap.
The Gulf Arab states have a long history with Iran and other hostile outsiders. The solution has always been to seek unity and outside allies. In the 19th century, the coastal emirates (city states that depended on trade, pearls, and fishing) allied themselves with Britain, for protection against the Turks (who controlled what is now Iraq), Iran (always a threat to the Arabs), and the interior tribes of Arabia. Britain was interested in suppressing pirates (which often operated out of the emirates) and halting Turkish expansion. In 1971, seven of the emirates formed a federation: the UAE (United Arab Emirates). There were immediate disputes with Saudi Arabia about where the land and water borders should be. Some of those disputes are still unresolved. The Saudis consider themselves the leader of Arabia, but most of the people in Yemen, Kuwait, Oman, and the UAE often disagree. There is a lot of friction. Nevertheless, in 1981, the Gulf Cooperation Council was formed by Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates. The UAE was the chief organizer of the council and has constantly quarreled with Saudi Arabia over leadership issues. But when it comes to outside threats, especially the Iranians, there is less quarrelling and a lot more cooperation. It's uncertain if this will be enough to thwart the Iranians. Only an actual war will reveal the reality of the situation.